Supplemental disclosure of cash flow information (Details Textual) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Redeemable Preferred Stock [Member]
Supplemental Disclosure Of Cash Flow Information [Line Items]
Stock Issued During Period, Shares, Issued for Services	7,409	9,441
Stock Issued During Period, Shares, Conversion of Convertible Securities	5,809	12,214
Common Stock [Member]
Supplemental Disclosure Of Cash Flow Information [Line Items]
Stock Issued During Period, Shares, Issued for Services	58,228	34,991